Both an unmanned vehicle and a manned vehicle may operate in a mine. An unmanned vehicle and a manned vehicle can collide with each other in operations in a mine. Further, when an unmanned vehicle and a manned vehicle collide with each other, part of the operations in the mine may need to be stopped for coping with the collision. Consequently, productivity in the mine lowers. There is required a technique capable of avoiding a collision between an unmanned vehicle and a manned vehicle in order to prevent a reduction in safety and a reduction in productivity in a mine. A technique for estimating a range in which a manned vehicle is present and preventing an interference between an unmanned vehicle and the manned vehicle is disclosed in Patent Literature 1. A technique for issuing an alarm for a possible collision between a vehicle and other vehicle is disclosed in Patent Literature 2.